The present invention relates generally to bactericides and fungicides, and, more specifically, to a bactericide/fungicide which is based upon a complex of copper and a partially neutralized polycarboxylic acid.
Bactericides/fungicides are known in the art as agents used to protect agricultural crops from damage caused by pathogenic bacteria/fungi. The use of such products is necessitated by the great losses caused by such organisms. To be economical, the cost of controlling plant diseases by the application of a bactericide/fungicide product must be offset by increased crop yield and quality.
Agricultural bactericides/fungicides are available in different types of formulations including wettable powders, emulsifiable concentrates, water-based flowables, and dry flowables (also known as water dispersible granules). Dry flowable products are generally dustless, free-flowing, granular products. Dry flowable formulations have recently gained in popularity among users because they offer advantages such as improved shelf life, substantially no dusting, easy pouring, a higher percentage of active ingredient, and more convenient packaging than other formulation types.
Copper based bactericides/fungicides are used extensively in agriculture. Several dry flowable copper based bactericides/fungicides are known in the art, these being: xe2x80x9cKocide DFxe2x80x9d available from Griffin Corporation of Valdosta, Ga.; xe2x80x9cBlueshield DFxe2x80x9d and xe2x80x9cNu-Cop WDGxe2x80x9d available from Micro Flo Company of Lakeland, Fla.; and xe2x80x9cSandoz COC DFxe2x80x9d and xe2x80x9cSandoz Cu2O DFxe2x80x9d available from Sandoz Ltd. of Switzerland.
Cupric hydroxide by itself is unstable. However, it is known in the art that cupric hydroxide can be stabilized by a phosphate process. U.S. Pat. No. Re. 24,324 (the disclosure of which is incorporated herein by reference) relates to a method of making stable cupric hydroxide. U.S. Pat. No. 3,428,731 (the disclosure of which is also incorporated herein by reference) relates to dispersions of phosphate stabilized cupric hydroxide. That patent discloses that aqueous dispersions of finely divided phosphate-process cupric hydroxide can be prepared by carefully regulating the pH of the dispersion and the calcium hardness of the aqueous vehicle. The patent also discloses that approximately 1% to 3% by weight of a dispersant should be added to the aqueous vehicle before the phosphate-process cupric hydroxide is added. Suitable dispersing agents are disclosed as including sodium lignosulfonate, the sodium salt of a polymeric carboxylic acid, sulfonated naphthalene, technical protein colloid, tallow dimethyl benzyl ammonium chloride, the sodium salt of polymerized alkyl aryl sulfonic acid, diethanolamide of a special fraction of coconut fatty acids, the sodium salt of condensed mono-naphthalene sulfonic acid and isooctyl phenyl polyethoxy ethanol.
The prior art copper based bactericide/fungicide products require the use of relatively large amounts of copper to effectively control disease. This relatively high level of copper detracts from cost effectiveness, contributes to soil residue problems and raises the potential for phytotoxicity. In addition, the methods used to produce these prior art products are not always cost effective.
Complexes of copper (II) ions with partially neutralized polyacrylic acid and with partially neutralized polymethacrylic acid in aqueous media are known. See for example F. Wall and S. Gill, xe2x80x9cInteraction of Cupric Ions with Polyacrylic Acid,xe2x80x9d J. Phys. Chem., Vol. 58, page 1128 (1954); A. Kotliar and H. Morawetz, xe2x80x9cChelation of Copper (II) with Polyacrylic and Polymethacrylic Acid,xe2x80x9d J. American Chem. Soc., Vol. 77, page 3692 (1955). Heretofore, complexes of copper with partially neutralized polycarboxylic acids have not been known to possess bactericidal or fungicidal properties. In particular, such complexes were not previously known to be an effective bactericide or fungicide for agricultural use; yet, also be substantially nonphytotoxic. Furthermore, such complexes were not previously known to be effective bactericides or fungicides against copper tolerant bacteria.
Therefore, a need exists for a copper-based bactericide/fungicide formulation which provides biological activity, particularly against copper tolerant bacteria, with substantially no phytotoxicity.
The present invention satisfies the above-described needs by providing an improved bactericide/fungicide and an improved method of making and using the same. The improved bactericide/fungicide of the present invention is prepared by forming an aqueous solution of a partially neutralized, water-soluble polycarboxylic acid having a molecular weight of between approximately 1,000 and 300,000 and a pH of between approximately 3 and 9. To this aqueous solution is added a copper-containing compound which when combined with said aqueous solution releases copper (II) ions which will form a water-soluble complex with said partially neutralized polycarboxylic acid.
The bactericide/fungicide of the present invention is used to control bacterial/fungal diseases in plants by applying to plants a bactericide/fungicide consisting essentially of a complex of copper and a partially neutralized, water-soluble polycarboxylic acid having a molecular weight of between approximately 1,000 and 300,000 and a pH of between approximately 3 and 9.
Accordingly, it is an object of the present invention to provide an improved bactericide/fungicide and an improved method of making and using the same.
Another object of the present invention is to provide a bactericide/fungicide which is substantially nonphytotoxic to the plants to which it is applied.
A further object of the present invention is to provide a bactericide/fungicide which can be made from a variety of different copper sources.
Yet another object of the present invention is to provide a bactericide/fungicide which can be used to control copper tolerant bacteria.
Another object of the present invention is to provide a bactericide/fungicide which can be used on plants and crops which are injured by conventional copper-based bactericides/fungicides when used at optimum rates for disease control.
Still another object of the present invention is to provide a bactericide/fungicide which is substantially water-soluble so that it can be relatively easily removed from crops or plants to which it is applied so that it can be applied to crops later in the growing cycle and/or post-harvest.
Another object of the present invention is to provide a bactericide/fungicide which does not leave a colored residue on the crops or plants to which it is applied.
A further object of the present invention is to provide a bactericide/fungicide which is useful in foliar applications for disease control.
Still another object of the present invention is to provide a bactericide/fungicide which requires a lower copper use rate for the same level of protection which would be provided by copper hydroxide-based bactericides/fungicides.
A further object of the present invention is to provide a bactericide/fungicide which can be used to pretreat seed prior to planting.
Another object of the present invention is to provide a bactericide/fungicide which will control bacteria and/or fungi growth on substrates of various materials.